Device for modifying the magnetization direction of a magnetic layer, spintronic system and associated method

Abstract

Device for modifying the direction of magnetization of a magnetic layer, spintronic system and associated method. The present invention relates to a device (12) for modifying at least the direction of magnetization of a magnetic layer (10), the modification device (12) comprising: - a ferroelectric layer (14) having a ferroelectric polarization, disposed on or under the magnetic layer (10) so as to define a stack (19) comprising at least the magnetic layer (10) and the ferroelectric layer (14), - a generator (16) adapted to inject an electric current into the stack in a direction parallel to the plane of the layers of the stack (19), and - a modification unit (18) adapted to modify the ferroelectric polarization of the ferroelectric layer (14), to allow, with the generator (16), modification of the direction of magnetization of the magnetic layer (10). Figure for the abstract: Figure 1

Description

Title of the invention: Device for modifying the magnetization direction of a magnetic layer, spintronic system and associated method

[0001] The present invention relates to a device for modifying at least the direction of magnetization of a magnetic layer. The present invention also relates to a spintronic system comprising such a device and to a method for modifying it.

[0002] Spintronic devices take advantage of the degree of freedom offered by the electron's spin to provide additional functionalities to conventional electronic devices, based on the electron's charge, such as the non-volatility of information. The term spin electronics or spintronics is used to refer to such a technology.

[0003] Applying a spin-polarized current to a ferromagnetic or ferrimagnetic element allows the direction of magnetization of that element to be manipulated. This spin-polarized current generates a so-called spin-transfer torque acting on the magnetization, which has, for example, been used in the operation of spintronic technologies such as magnetic random-access memory, based on spin transfer through a tunnel junction. In these memories, the current is applied perpendicular to the plane of a magnetic tunnel junction, which makes it possible to reverse the magnetization of one of the layers composing the junction.

[0004] Another way to reverse magnetization by applying current is based on so-called spin-orbit torques. These torques appear in bilayers made of a spin Hall effect material, typically a heavy metal (such as Pt, Pd, W, Ta), in contact with a ferromagnetic or ferrimagnetic material such as Co or CoFeB. They can also appear via the Rashba-Edelstein effect at the interface between the ferromagnetic or ferrimagnetic element and the ferroelectric element. The spin Hall effect and / or the Rashba-Edelstein effect make it possible to convert a charge current flowing in the plane of a stack into a spin current perpendicular to the plane of the stack. This spin current can cause the magnetization of the magnetized layer to oscillate and / or reverse its magnetization.

[0005] This technique of modifying the magnetization orientation by spin-orbit pair is, for example, used to create random-access magnetic memories based on spin-orbit pairs, in which the information encoded in the magnetization state of the ferromagnetic or ferrimagnetic element can be reversed by applying a current in the plane of the layers. This technique can also be used to create shift register-type devices, consisting of tracks in In these systems, information is encoded via magnetic inhomogeneities, such as magnetic walls or skyrmions, which can be displaced by spin-orbit pairs. This technique can also be used in spin-orbit oscillators, where the spin current generated by an in-plane charge current sustains magnetization oscillations, thereby generating radio frequency signals.

[0006] The fundamental element of these spin-orbit couple-based devices is often a layer of spin Hall-effect material in contact with the ferromagnetic or ferrimagnetic element. A charging current in the plane of the stack is converted into a spin current by the spin Hall effect. This conversion between charging current and spin current is determined by the nature of the layer stacking. The change in the magnetization direction is therefore controlled solely by the current flowing in the plane of the stack.

[0007] There is therefore a need for a device for modifying at least one magnetic property of a magnetic layer that offers more degrees of freedom for a spintronic system that would include such a modification device.

[0008] For this purpose, the present description relates to a device for modifying at least the direction of magnetization of a magnetic layer, the modification device comprising a ferroelectric layer having a ferroelectric polarization, arranged on or under the magnetic layer so as to define a stack comprising at least the magnetic layer and the ferroelectric layer, a generator capable of injecting an electric current into the stack in a direction parallel to the plane of the layers of the stack, and a modification unit suitable for modifying the ferroelectric polarization of the ferroelectric layer to allow, with the generator, the modification of the direction of magnetization of the magnetic layer.

[0009] A means of modifying the direction of the magnetization is thus proposed, in which this modification depends both on a current flowing in the plane of the stack and, in a non-volatile manner, on the polarization of a ferroelectric layer, in particular by applying a voltage to said ferroelectric layer. Indeed, the device uses a ferroelectric layer, the polarization state of which allows the spin-orbit couple to be modified.

[0010] This additional degree of freedom will allow the addition of functionalities to these devices, such as logic functions in addition to memory, or even reprogrammability.

[0011] According to particular embodiments, the modification device has one or more of the following characteristics, taken individually or in all technically possible combinations:

[0012] - the ferroelectric polarization modification unit is a voltage source.

[0013] - the magnetic layer is in contact with the ferroelectric layer.

[0014] - at least one layer among the magnetic layer and the ferroelectric layer is nanostructured.

[0015] - the stack comprises an intermediate layer interposed between the ferro- layer electrical and magnetic layer, the intermediate layer advantageously comprising a material chosen from the following list taken alone or in combination: a metal, in particular platinum or tungsten, a Weyl semi-metal, a two-dimensional material, in particular graphene, a dichalcogenide of transition metals, and a topological insulator.

[0016] - the ferroelectric layer is in contact with a protective layer,

[0017] The description also describes a spintronic system comprising a magnetic layer, a device for modifying at least the direction of magnetization of the magnetic layer, the modification device being as previously described, and a unit for reading the magnetization of the magnetic layer, the reading unit being, for example, a magnetic tunnel junction.

[0018] According to a particular embodiment, the spintronic system is chosen from a memory, a shift register, an oscillator, part of a logic or neuromorphic device, and a radio frequency transmitter or receiver.

[0019] The description also relates to a method of modifying at least the magnetization direction of a magnetic layer, the method comprising a step of modifying the magnetization of the magnetic layer by modifying the ferroelectric polarization of a ferroelectric layer disposed on or under the magnetic layer, so as to define a stack comprising at least the magnetic layer and the ferroelectric layer, and by injecting an electric current into the stack in a direction parallel to the plane of the layers of the stack.

[0020] According to a particular embodiment, the modification of the ferroelectric polarization is implemented by applying an electric voltage to the ferroelectric layer.

[0021] Other features and advantages of the invention will become apparent from the following description of embodiments of the invention, given by way of example only and with reference to the drawings which are:

[0022] - [fig. 1][fig. 1], a schematic representation of a magnetic layer and a example of a device for modifying at least one magnetic property of the magnetic layer,

[0023] - [fig.2][fig.2], a schematic representation of an example of a spin system electronics,

[0024] - [fig.3][fig.3], a schematic representation of another example of a spin system electronics, and

[0025] - [fig.4][fig.4], a schematic representation of the magnetic layer and another example of a device for modifying at least one magnetic property of the magnetic layer.

[0026] As the present invention is based on a new technique for modifying a magnetic property of a magnetic layer, it is first presented how to physically implement such a technique by describing a specific modification device before explaining how such a modification device makes it possible to obtain a spintronic system which offers more functionality thanks to the degrees of freedom obtained by this new technique.

[0027] Fig. 1 thus presents a physical implementation of the aforementioned new technique. More specifically, a magnetic layer 10 and a modification device 12 are shown in Fig. 1.

[0028] By definition, the magnetic layer 10 is a ferromagnetic and / or ferrimagnetic monolayer or multilayer. In other words, the material or set of materials forming the monolayer or multilayer constitute a ferromagnetic and / or ferrimagnetic assembly even if some of the materials forming part of said layer are intrinsically non-ferromagnetic and / or non-ferrimagnetic.

[0029] According to a first example, the magnetic element of this spin-polarizing mono or multilayer is a Heusler alloy, for example Cu2MnAl, Cu2MnIn, Cu2MnSn, NfiMnAl, NfiMnln, NfiMnSn, NfiMnSb, Ni2MnGa Co2MnAl, Co2MnSi, Co2MnGa, Co2MnGe, Pd2MnAl, Pd2MnIn, Pd2MnSn, Pd2MnSb, Co2FeSi, Co2FeAl, Fe2VAl, Mn2VGa, Co2FeGe, MnGa, or MnGaRu.

[0030] In a second example, the ferromagnetic and / or ferrimagnetic material is based on 3d elements such as Fe, Ni, Cr, Mn, Co, used pure or in the form of multi-layers or alloys, with each other or with other elements, such as CoPtCr, CoFe, CoFeB, CoNi, NiFe, FePt or FePd.

[0031] In a third example, the ferromagnetic and / or ferrimagnetic material may comprise rare earth-based alloys, such as Nd, Sm, Eu, Gd, Tb, or Dy.

[0032] In a fourth example, the ferromagnetic and / or ferrimagnetic material may comprise nitrogen compounds such as Mn4N.

[0033] The magnetic layer 10 has a thickness between 0.1 nanometer (nm) and 200 nm.

[0034] By definition, the thickness is the distance between the two faces of the magnetic layer 10 in the direction perpendicular to the plane in which the magnetic layer 10 mainly extends.

[0035] Preferably, the thickness of the magnetic layer 10 is between 0.1 nm and 20 nm.

[0036] The magnetic layer 10 has magnetic properties including magnetization.

[0037] The magnetization of this magnetic layer is its volume magnetic moment density. This magnetization is a vector quantity, and it is not necessarily uniform within the layer; that is, its direction varies from one point to another within the magnetic layer. The direction of magnetization of the magnetic layer is understood to be the direction of magnetization at each point of this layer. A change in the direction of magnetization of the layer can therefore affect the entire layer or only a part of it.

[0038] The modification device 12 is a modification device 12 of at least one magnetic property of the magnetic layer 10.

[0039] In the example described, the modification device 12 is suitable for modifying the magnetization direction of the magnetic layer 10.

[0040] The modification device 12 comprises a ferroelectric layer 14, a current generator 16 and a modification unit 18.

[0041] The ferroelectric layer 14 is arranged on or under the magnetic layer 10 so as to define a stack 19 comprising at least the magnetic layer 10 and the ferroelectric layer 14.

[0042] In the example of [fig. 1], the ferroelectric layer 14 is in contact with the magnetic layer 10.

[0043] The ferroelectric layer 14 is composed of a mono or multilayer comprising one or more materials ensuring ferroelectric properties to the resulting layer.

[0044] According to the example in [fig.1], the ferroelectric layer 14 comprises a material advantageously having a perovskite structure.

[0045] For example, the ferroelectric layer 14 comprises BaTiO3, PZT, PMN-PT, BiFeO3, or SrTiO3, or another ABO3 type element where A and B are two cations, or a mixture of these materials.

[0046] The acronym PZT designates the element PbZri xTixO3 where x can vary between 0 and 1.

[0047] Elements such as BiFeO3 or SrTiO3 may optionally be doped. For example, BiFeO3 may be doped with rare earth elements.

[0048] Alternatively, ferroelectric materials not exhibiting a perovskite structure are conceivable. In particular, poly(vinylidene fluoride) (also designated by the acronym PVDF, referring to the English term "Polyvinylidene Fluoride") or CsBiNb2O7 or the element (Hfi xZrx)O2 or (Hfi xGax)O2 (with x varying between 0 and 1) may be mentioned.

[0049] Alternatively, two-dimensional ferroelectric materials such as transition metal dichal-cogenides, such as WTe2 or MoS2 or MoSe2, or CuInP2S6 can be used.

[0050] As an alternative, ferroelectric Rashba semiconductor materials such as GeTe or Gei xMnxTe (with X varying between 0 and 1), possibly doped or substituted with Sn, or AgBiP2X6 (X = S, Se and Te), or LiZnSb, LiGaGe, KMgSb, LiBeBi, NaZnSb, LiCaBi can be used.

[0051] Alternatively, the material may be a material which is not spontaneously ferroelectric but which can become ferroelectric by applying a stress, or an electric field, or by doping.

[0052] The ferroelectric layer 14 exhibits a ferroelectric polarization.

[0053] The ferroelectric layer 14 has a suitable thickness so that its polarity the risation can be reversed. As an indication, in the field of microelectronics for which compatible voltages are generally less than 10 Volts, typically a thickness less than 100 nm and advantageously less than 50 nm is an appropriate thickness.

[0054] In the example of [fig.l], it is the modification unit 18 which is responsible for modifying the ferroelectric polarization of the ferroelectric layer 14.

[0055] According to the example proposed, the modification unit 18 is a voltage source, the variation of the voltage allowing the polarization to be modified.

[0056] An example of a voltage source is a voltage generator supplying the ferroelectric layer 14. This voltage generator is then connected to the stack 19 by contacts arranged for example on either side of the stack 19.

[0057] According to another example of a voltage source, this is a transistor or a set of transistors made for example by integrated circuits and electrically connected to the ferroelectric layer 14.

[0058] Furthermore, the current generator 16 is suitable for injecting current into the stack 19 in a direction parallel to the plane of the layers of the stack 19.

[0059] The layer plane of the stacking 19 is a plane in which the layers of the stacking 19 extend.

[0060] The modification unit 18 is thus able to modify the ferroelectric polarization of the ferroelectric layer 14, to allow with the generator 16 to modify the direction of magnetization of the magnetic layer 10.

[0061] Indeed, the magnetization direction of the magnetic layer 10 is linked to the ferroelectric polarization of the ferroelectric layer 14 and to the electric current flowing in the stack 19.

[0062] In other words, the polarization of the ferroelectric layer 14 and the application of a current in the stack 19 together allow the direction of the magnetization of the magnetic layer 10 to be controlled.

[0063] This implies that the ferroelectric layer 14 is spatially arranged with respect to the magnetic layer to change the direction of its magnetization under the effect of the current injected by the current generator 16.

[0064] More specifically, in operation, the modification device 12 converts the charge motion (charge current) from the current injected by the current generator 16 into a spin magnetic moment flux (spin current) in the magnetic layer.

[0065] Such a charge current to spin current conversion is, for example, obtained by the Rashba-Edelstein effect.

[0066] The Rashba-Edelstein effect allows the conversion of a charge current into a spin current at the surface of a topological insulator or at an interface or within the volume of certain materials. It appears when the inversion symmetry is broken, resulting in the appearance of an electric field perpendicular to the stacking plane 19. This is, for example, possibly the case at the interface between the magnetic layer 10 and the ferroelectric layer 14.

[0067] In the presence of a Rashba-Edelstein effect, the wave vector of the electrons and the spin are coupled; the spin degeneracy is lifted and in the simplest case, the electronic structure of the surface or interface consists of two concentric Fermi contours exhibiting opposite spin chiralities.

[0068] When a charge current is injected by the current generator 16 into the stack 19, the Rashba-Edelstein effect causes an opposite but non-equivalent shift of the Fermi contours to occur, which generates a spin current.

[0069] Since the amplitude of the Rashba-Edelstein effect depends on the direction of the polarization of the ferroelectric layer 14, the aforementioned conversion also depends on it, so that the spin current and therefore the magnetization direction also depends on it.

[0070] Controlling the state of the polarization of the ferroelectric layer 14 therefore makes it possible to control the properties of the spin current flowing in the magnetic layer 10 after injection of a charge current and thus to modify the direction of magnetization.

[0071] Alternatively, if the stack 19 includes a spin Hall effect material, the charge current to spin current conversion can be obtained by spin Hall effect, and again, the polarization of the ferroelectric layer 14 allows control of the amplitude of the spin Hall effect conversion and therefore the magnetization of the magnetic layer 10.

[0072] In all cases, the modification device 12 is thus suitable for implementing a method of modifying the direction of magnetization of the magnetic layer 10.

[0073] The process includes a step of modifying the magnetization of the magnetic layer 10 by modifying the ferroelectric polarization of the ferroelectric layer 14 and by injecting an electric current into the stack 19 in a direction parallel to the plane of the layers of the stack 19.

[0074] In the case of [fig.1], the modification of the ferroelectric polarization is implemented by applying an electric voltage to the ferroelectric layer 14.

[0075] The modification unit 18 therefore makes it possible to control the direction of magnetization of the magnetic layer 10 provided that a charging current is injected into the stack 19.

[0076] The additional degree of freedom provided by the voltage makes it possible to consider using the modification device 12 in a spintronic system so that the magnetic layer 10 can provide, in combination with other elements, complementary functionalities such as memorization or reprogrammability.

[0077] The modification device 12 is thus particularly advantageous in a spintronic system 30 as represented in [fig.2].

[0078] The spintronic system 30 includes the magnetic layer 10, the modification device 12 of [fig.1] and a reading unit 32 of the magnetization of the magnetic layer 10.

[0079] The reading unit 32 of the magnetization of the magnetic layer 10 is suitable for determining the direction of the magnetization of the magnetic layer 10.

[0080] According to the example in [fig.2], the reading unit 32 is a magnetic tunnel junction.

[0081] A magnetic tunnel junction is a stack of a magnetic layer separated from a free layer by a barrier layer. The free layer is the layer that can flip under the effect of the spin-orbit couple. The barrier layer is, for example, made of MgO or Al₂O₃.

[0082] In some cases, as seen in [fig.3], the reading unit 32 is positioned above the stack 19.

[0083] According to one variant, the reading unit 32 is positioned below the stack 19.

[0084] Other embodiments are possible for the reading unit 32. In particular, the reading unit 32 can be a stack of giant magnetoresistance layers, an extraordinary Hall effect reading unit in the magnetic layer 10, a planar Hall effect reading unit, or an anisotropic magnetoresistance reading unit.

[0085] In each case, the reading unit 32 makes it possible to obtain information which is encoded in the magnetic properties of the magnetic layer 10.

[0086] For example, when the spintronic system 30 is a memory, the information is coded in the direction of magnetization of the magnetic layer 10.

[0087] In other embodiments, the information is encoded in the positions or configurations of magnetic inhomogeneities such as domain walls, skyrmions or spin waves propagating in the magnetic layer 10.

[0088] In such a case, modifying the ferroelectric polarization makes it possible to modify the propagation of one of the aforementioned elements (wall / skyrmion / spin wave). The modification can be a change in speed (acceleration or deceleration, or even stopping) or in amplitude (amplification or attenuation).

[0089] In such an application, the control device 12 therefore provides an additional degree of freedom resulting in an improvement of the function performed by the control device 12.

[0090] Such an input is advantageous for multiple spintronic systems 30, including a memory, a shift register, part of a logic or neuromorphic device, an oscillator, a radio frequency transmitter or a radio frequency receiver.

[0091] To improve the properties of such spintronic systems 30, other embodiments of the modification device 12 are conceivable.

[0092] Thus, by way of example, another modification device 12 is shown in [fig.4],

[0093] The modification device 12 of [Fig. 4] has the same elements as the modification device 12 of [Fig. 1]. Therefore, the common elements are not repeated in what follows. Only the differences are presented below.

[0094] In the case of [fig.4], the modification device 12 further comprises an intermediate layer 34 interposed between the magnetic layer 10 and the ferroelectric layer 14.

[0095] The intermediate layer 34 can be made of multiple materials.

[0096] For example, the intermediate layer 34 is made of a spin-orbit material and has a thickness of less than 50 nm and advantageously less than 10 nm

[0097] A spin-orbit material is a material that allows a charge current to be converted into a spin current.

[0098] In such a case, the spin-orbit material is advantageously one of the following: beta-Tantalum (beta-Ta), BiSb, Ta, beta-Tungsten (beta-W), W, Pt and Cu or Au doped with elements from columns 3d, 4d, 5d, 4f, 5f of the periodic table such as W, Ta or Bi.

[0099] According to another example, the intermediate layer 34 may comprise a two-dimensional material, possibly doped, alone or in combination with other materials.

[0100] Graphene, BiSe2, BiS, TiS, NiPS3, WS2, MoS2, TiSe2, VSe2, MoSe2, B2S3, Sb2S, LaCPS2, LaOAsS2, ScOBiS2, FePS3, GaOBiS2, AIOBiS2, LaOSbS2, BiOBiS2, LaOBiSe2, TiOBiS2, CeOBiS2, PrOBiS2, NdOBiS2, LaOBiS2, CrGeTe3, CrSiTe3 or SrFBiS2 are examples of two-dimensional materials.

[0101] Alternatively, the intermediate layer 34 may comprise a Weyl semi-metal alone or in combination with other materials.

[0102] TaAs, TaP, NbAs, NbP, Na3Bi, Cd3As2, WTe2 and MoTe2 are examples of Weyl semi-metals that can be used in the intermediate layer 34.

[0103] According to another example, the intermediate layer 34 comprises a topological insulator. A topological insulator is a material having an insulating-type strip structure but which has metallic surface states.

[0104] Bi2Se3, BiSexTe2 x (x being between 0 and 2), BiSbTe, SbTe3 and HgTe are examples of topological insulators that can be used in the intermediate layer 34.

[0105] Alternatively, the intermediate layer 34 may comprise a dichalcogenide of transition metals.

[0106] Preferably, in such a case, the material of the intermediate layer 34 is a material having a chemical formula written ROCh2 in which the element R is chosen from the list consisting of La, Ce, Pr, Nd, Sr, Sc, Ga, Al and In and the element Ch is chosen from the list consisting of S, Se and Te.

[0107] Such types of materials exhibit a satisfactory spin-orbit effect for the intermediate layer 34.

[0108] In summary, the material of the intermediate layer 34 is advantageously a spin-orbit material and in particular a Weyl semi-metal and / or a topological insulator and / or a two-dimensional material and / or a dichalcogenide of transition metals and / or an oxide (for example LaA103) and / or even a metal such as platinum or tungsten.

[0109] The operation of the modification device 12 according to [fig.4] is similar to the operation described for the modification device 12 according to [fig. 1].

[0110] Other embodiments are also possible.

[0111] For example, the ferroelectric layer 14 is in contact with a protective layer.

[0112] The protective layer makes it possible to create and / or protect an electron gas forming on the surface of the ferroelectric layer 14 and to improve the growth of the layers of the spintronic system 30 during its manufacture.

[0113] In a particular case, the protective layer is made of Ru, Al, Ta, Ti or Y.

[0114] According to another embodiment or in addition, the magnetic layer 10 is nanostructured.

[0115] Such nanostructuring can in particular be achieved by using a lithography technique.

[0116] This makes it possible, for example, to obtain a set of nanoelements having one or more dimensions in the stacking plane of less than 100 nm. Such a configuration guration is advantageous in the case of memories or parts of neuro-morphic devices.

[0117] According to another example, this makes it possible to produce nanotracks, in particular tracks with a width of less than 200 nm, suitable for the case of devices based on the use of domain walls or skyrmions.

[0118] In certain applications, as an alternative or in addition, the ferroelectric layer 14 is nanostructured.

[0119] A person skilled in the art will understand that the modification device 12 can comprise any combination of the aforementioned embodiments.

[0120] In each case, the modification device 12 makes it possible to modify at least one magnetic property of a magnetic layer (the magnetization direction here) which offers more degrees of freedom for a spintronic system 30 which would include such a modification device 12.

Claims

Claims

1. Device (12) for modifying at least the magnetization direction of a magnetic layer (10), the modification device (12) comprising: - a ferroelectric layer (14) having a ferroelectric polarization, arranged on or under the magnetic layer (10) so as to define a stack (19) comprising at least the magnetic layer (10) and the ferroelectric layer (14), a plane in which the layers of the stack (19) extend being defined, - a generator (16) capable of injecting an electric current into the stack (19) in a direction parallel to the plane of the layers of the stack (19), and - a modification unit (18) capable of modifying the ferroelectric polarization of the ferroelectric layer (14), to allow with the generator (16) to modify the magnetization direction of the magnetic layer (10).

2. A modification device according to claim 1, wherein the ferroelectric polarization modification unit (18) is a voltage source.

3. A modification device according to claim 1 or 2, wherein the magnetic layer (10) is in contact with the ferroelectric layer (14).

4. A modification device according to any one of claims 1 to 3, wherein at least one of the magnetic layer (10) and the ferroelectric layer (14) is nanostructured.

5. Modification device according to any one of claims 1 to 4, in which the stack comprises an intermediate layer (34) interposed between the ferroelectric layer (14) and the magnetic layer (10), the intermediate layer (34) advantageously comprising a material chosen from the following list taken alone or in combination: - a metal, in particular platinum or tungsten, - a Weyl semi-metal, - a two-dimensional material, in particular graphene, - a transition metal dichalcogenide, and - a topological insulator.

6. A modification device according to any one of claims 1 to 5, wherein the ferroelectric layer (14) is in contact with a protective layer,

7. Spintronic system (30) comprising: - a magnetic layer (10), - a modification device (12) of at least the magnetization direction of the magnetic layer (10), the modification device (12) being according to any one of claims 1 to 6, and - a reading unit (32) of the magnetization of the magnetic layer (10), the reading unit (32) being, for example, a magnetic tunnel junction.

8. Spintronic system according to claim 7, wherein the spintronic system (30) is chosen from: - a memory, - a shift register, - an oscillator, - a part of a logic or neuromorphic device, and - a radiofrequency transmitter or receiver.

9. Method for modifying (12) at least the magnetization direction of a magnetic layer (10), the method comprising: - a step of modifying the magnetization of the magnetic layer (10) by modifying the ferroelectric polarization of a ferroelectric layer (14) arranged on or under the magnetic layer (10) so as to define a stack comprising at least the magnetic layer (10) and the ferroelectric layer (14), a plane in which the layers of the stack (19) extend being defined, and by injecting an electric current into the stack (19) in a direction parallel to the plane of the layers of the stack (19).

10. The method of claim 9, wherein the modification of the ferroelectric polarization is implemented by applying an electrical voltage to the ferroelectric layer (14).

Images